Ether-bridged dication, ionic liquid electrolyte and charge storage device thereof

Abstract

An ether-bridged dication is provided with two monovalent cations bonded via a carbon chain having ether group(s). The ether-bridged dication, monovalent cations, and anions are contained together within an ionic liquid electrolyte which is applied to a charge storage device. The ether-bridged dication, the ionic liquid electrolyte, and the charge storage device have operational abilities at room temperatures or below, and a reachable working potential of 3.5 V.

What is claimed is: 
     
         1 . An ether-bridged dication with two monovalent cations, X 1  and X 2 , bonded through a carbon chain having at least one ether group, having the molecular structure given as follows: 
       
         
           
           
               
               
           
         
         wherein X1 and X2 are independently selected from a quaternary ammonium cation, a sulfonium cation, and a phosphonium cation; and 
         each of a, b and c is an integral selected from 1 to 10. 
       
     
     
         2 . The ether-bridged dication according to  claim 1 , wherein the quaternary ammonium cation is selected from an imidazolium cation, a pyrrolium cation, a pyridinium cation, a pyrazolium cation, a benzimidazolium cation, an indolium cation, a carbazolium cation, a quinolium cation, a pyrrolidinium cation, a piperidium cation, a piperalium cation, and an alkyl ammonium cation. 
     
     
         3 . The ether-bridged dication according to  claim 2 , wherein the imidazolium cation is 
       
         
           
           
               
               
           
         
       
     
     
         4 . The ether-bridged dication according to  claim 2 , wherein the pyrrolium cation is 
       
         
           
           
               
               
           
         
       
     
     
         5 . The ether-bridged dication according to  claim 1 , wherein the sulfonium cation is an alkyl sulfonium cation. 
     
     
         6 . The ether-bridged dication according to  claim 5 , wherein the alkyl sulfonium cation is a trimethyl sulfonium cation ((CH 3 ) 3 S + ). 
     
     
         7 . The ether-bridged dication according to  claim 1 , wherein the phosphonium cation is an alkyl phosphonium cation. 
     
     
         8 . The ether-bridged dication according to  claim 7 , wherein the alkyl phosphonium cation is a butyl triethyl phosphonium cation ((C 2 H 5 ) 3 C 4 H 9 P + ). 
     
     
         9 . The ether-bridged dication according to  claim 1 , wherein the ether-bridged dication is 
       
         
           
           
               
               
           
         
       
     
     
         10 . An ionic liquid electrolyte, comprising:
 an ether-bridged dication according to  claim 1 ;   at least one monovalent cation; and   at least one anion;   wherein the ionic liquid electrolyte is formed without organic solvents.   
     
     
         11 . The ionic liquid electrolyte according to  claim 10 , wherein the ether-bridged dication is 2-20 wt % of the ionic liquid electrolyte. 
     
     
         12 . The ionic liquid electrolyte according to  claim 10 , wherein the monovalent cation is selected from a quaternary ammonium cation, a sulfonium cation, and a phosphonium cation. 
     
     
         13 . The ionic liquid electrolyte according to  claim 10 , wherein the anion is selected from [BF 4 ] − , [PF 6 ] − , a Bis(fluorosulfonyl)imide anion, and a Bis(trifluorosulfonyl)imide anion. 
     
     
         14 . A charge storage device, comprising an ionic liquid electrolyte according to  claim 10 . 
     
     
         15 . The charge storage device according to  claim 14 , wherein the charge storage device has a specific capacitance of more than 160 F/g at −20° C. 
     
     
         16 . The charge storage device according to  claim 14 , wherein the charge storage device has a reachable working potential of 3.5 V.